Normal Map Node - Can't See A Difference In Render
You have the mapping nodes in the wrong place. The image texture should be connected to the normal map node, the mapping node should be connected to the vector input of the image texture.

To keep the two image textures aligned, connect them to the same mapping node.

You should also change the colour space for a normal map to Non-Colour.

Note that the mapping node looks different in 2.81